Before introducing his Justice Department picks from Wilmington, Delaware, on Thursday, Biden offered comments on Wednesday's chaos at the Capitol which he deemed "one of the darkest days in the history of our nation" and "an unprecedented assault on our democracy."

"All of us here grieve the loss of life, grieve the desecration of the people's house. But what we witnessed yesterday was not dissent. It was not disorder. It was not protests. It was chaos," Biden said. "They weren't protesters. Don't dare call them protesters. They were a riotous mob, insurrectionists, domestic terrorists."

Biden placed blame on Trump who, he said, for the past four years has "made his contempt for our democracy, our Constitution, the rule of law clear in everything he has done."

"He unleashed an all-out assault on our institutions of our democracy from the outset. And yesterday was but the culmination of that unrelenting attack," Biden said.

Biden also predicted the response would have been very different had the majority of rioters been Black.

"No one can tell me that if it had been a group of Black Lives Matter protesting yesterday, there wouldn't have been -- they would have been treated very, very differently than the mob of thugs that stormed the Capitol. We all know that's true, and it is unacceptable, totally unacceptable," he said.

House Speaker Nancy Pelosi has called on Vice President Mike Pence to invoke the 25th Amendment to remove Trump from office for his "seditious acts" following Wednesday's rioting at the Capitol, she said at a press conference Thursday.

The California Democrat is threatening impeachment proceedings if Pence does not.

-ABC News' Mariam Khan

Senate Majority Leader Mitch McConnell put out a statement Thursday, saying the riots within the Capitol Building Wednesday represent "a massive failure" of "institutions, protocols, and planning that are supposed to protect the first branch of our federal government."

"A painstaking investigation and thorough review must now take place and significant changes must follow," McConnell added. "Initial bipartisan discussions have already begun among committees of oversight and Congressional Leadership."

-ABC News' Allison Pecorin

Transportation Secretary Elaine Chao is resigning from her position in the wake of rioting at the U.S. Capitol.

She cites the storming of the Capitol by "supporters of the President" as an "entirely avoidable event" in a letter she is sending out to her colleagues announcing her resignation.

"Yesterday, our country experienced a traumatic and entirely avoidable event as supporters of the President stormed the Capitol building following a rally he addressed. As I'm sure is the case with many of you, it has deeply troubled me in a way that I simply cannot set aside," Chao said.

Chao is married to Senate Majority Leader Mitch McConnell.

In an interview on Fox News Monday morning, Republican senatorial candidate David Perdue said that while he and his wife have "repeatedly" tested negative for coronavirus, he is still quarantining after coming into "close contact" last week with a campaign staffer who tested positive and hopes to participate in

"I’m going to participate hopefully tonight by virtually in this rally, but I’m so excited that President Trump is coming again," Perdue said, going on to paint the dire picture of the country if Democrats win.

Asked what he wants to hear the president say Monday, Perdue said: "First of all this is the last opportunity we will have to protect everything that we’ve accomplished in the last four years. The second thing is the last line of defense to stop the Democrats from perpetrating this radical socialist agenda. It’s as simple as that." 

As he did Sunday, Perdue blasted disclosure of the call between Trump and Secretary of State Brad Raffensperger and defended the president.

"To have a state-wide elected official, regardless of party, tape unknowing -- to tape without disclosing a conversation -- private conversation of the president of the United States and then leaking it to the press is disgusting," Perdue said.

When asked if he was concerned that GOP voters may be discouraged from participating in the aftermath of a general election Republicans continue to contest, Perdue said, "Well that’s what the Democrats want." Trump himself acknowledged post-election chaos may hinder turnout in the runoffs during his call with Raffensperger Saturday -- and blamed the secretary for it.

-ABC News’ Quinn Scanlan